As for me, I think Lugia should be a Psychic/Flying. But, as for any difficult question, research is always in order.
Example:
Lugia are thought to be the leaders of the legendary birds of Kanto. Much like the birds, it possesses the ability to control the weather, most notably it can calm storms. They are highly intelligent, and because of the devastating power it could accidentally inflict, it isolates itself deep underwater. |
To elaborate, Lugia are able to control the whether. How else but with Psychic powers.
In conclusion, it's psychic-type for its ability to control the weather and it only lives in the water to protect other people from its awesome powers. As for being the 'polar opposite' of Ho-Oh, the dex entries never once stated that. That is simply an observation by the fans. So it has never been explicitly stated by anyone or anything other than a fan that it is Ho-Oh's polar opposite, thus that's not a good back-up argument.
Using Lugia's Psychic-type to justify its weather-controlling ability is not good, either. Groudon and Kyogre can both alter the weather with the abilities Drought and Drizzle respectively; they're not Psychic-type. Though Rayquaza cannot physically alter weather, it can negate weather effects with the Air Lock ability. It's not Psychic-type either.
Even Tyranitar, Hippowdon, and Abomasnow can alter the weather (Sand Stream and Snow Warning), and they're not even legendary, let alone Psychic-type. To "calm storms", as the Dex Entry says, Lugia could equally have Air Lock/Cloud Nine as its ability, essentially negating the effects of "storms" (Rain Dance's Water-type boost, Thunder's no-miss accuracy in rainfall). However, that would draw from Rayquaza's uniqueness.
With Lugia as Water/Flying, the creators could still let it possess a Psychic movepool, if it absolutely needs one. Even though the ability would be more fitting for Articuno, Lugia could have Snow Warning to display a unique weather-altering power. (The only reasons I'm doing a Hail-based ability are:
1. As Lugia is the Guardian of the Sea, and Hail is composed of ice (derived from water), the element fits. Again, I believe Articuno is more fitting for Snow Warning, though it would disrupt the equal abilities of its trio.
*I know a Snow Warning Lugia would hurt itself with Hail, but Groudon and Kyogre
potentially set themselves up for KOs with their abilities (speedy Pkmn using Solarbeam on Groudon with Drought/Thunder on Kyogre with Drizzle)
2. Hail (transformed water) could be seen as a counter to Ho-oh. Instead of Pressure, Ho-oh could have Drought (since it is associated with fire and the sun).
3. Hail would give Lugia a weather-altering power without the need to go Psychic-type.
As for a Water/Flying Lugia, that is only to be seen as a counterpart to Ho-oh. While not stated to be polar opposites, many of Lugia's and Ho-oh's respective associations counter each other. Also, both Pokemon equally get a 4x weakness. Ho-oh gets an additional weakness to water because of its higher attacking stats.
Also, to preserve "uniqueness" (among legendaries only), if Groudon lost Drought to Ho-oh, it could take up Sand Stream instead, as that is its primary type. However, Groudon w/Drought better fits among the surrounding legends.
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I'd like mainly Gyarados (and maybe Charizard, though I like that its Flying-type suits its ACTUAL ABILITY TO FLY!) to be Dragon-type, too sadly, that could make them too over-powered. However, changes could be made in stats and movepools to lessen the threat and retain the Dragon-typing.
I got annoyed about the Bagon > Shelgon =/= Flygon, since the names are very suggestive of such a dragon family, rather than Salamence, which hints more towards salamander. But, I guess I can let Salamence be the "menace" that it is. ;) And anyway, "Flygon"could doubly imply that it's a dra
gonfly...
And lastly, WHY didn't they make Yanmega Bug/Dragon? It's a much better type combo than the repetitive Bug/Flying we've seen like a thousand times already.
Now how are we going to get a Bug/Dragon Pokemon?
All these inconsistencies just make me wanna get PokeSav and alter abilties and types to fit! Sigh... Anyway, it's just my
opinion.
*When I'm dealing with Lugia and the like, I'm more concerned with the legends fitting the Pokemon rather than the Pokemon fitting the competitive scene. I'm not really that competitive, but I'll use competitive Pokemon sets if I need/want to. Sorry for the long post!